The primary outcome will be prevalence of ear infection at seven months of age, defined as middle ear effusion or tympanic membrane perforation or acute otitis media. Pneumatic otoscopy, video-otoscopy and tympanometry will be used in the ear examinations. The primary analyses will be a direct comparison of the proportion of infants in the control group (Group C) who have nasopharyngeal carriage of vaccine type pneumococci at seven months of age compared to infants in each of the other two groups and a similar comparison of the proportion with middle ear disease.